Recipient - Caprice with power driver bucket or power driver split bench. If all manual, you could do this with a Caprice power seat track for driver or both sides. I believe the bolts and nuts attaching the track to the floor are 13mm.
Remove the Caprice front seats. For the driver side, run the seat full up and back and remove the rear bolts attaching the seat to the track. Run the seat full forward and remove the two front bolts. The seat should lift off of the seat track.
Remove the two front and four rear nuts, unconnect the body harness to motor wiring harness connector, and remove the seat track.
If the Bonneville seats still have the power track attached, mark and unconnect the motor wiring harness connectors (4 motor connectors). Mark and remove the motor wiring harness connector from the Caprice seat track (3 motor connectors) and plug this into the Bonneville seat track. The motor in the middle of the seat bottom is the recline motor - don't connect here, connect to the three motors on the side of the track. You can then drop the seat in the car, connect the body harness connector to move the seat around to remove it from the Pontiac tracks. You'll also see that the only basic difference in the two tracks is the track to floor pan mounts.
After you've separated both seats from tracks, you'll need to redrill the Caprice seat track rails to match the Pontiac welded nut holes in the seat bottom frame. After reattaching the Pontiac motor harness to the Caprice seat track and attaching the Pontiac seat to the Caprice seat track, you're ready to bolt the seat in the car - but wait.
Removing the passenger side is very basic if it's manual as mine was. Unbolt from floor and seperate seat and track outside the car. To use the Caprice manual track on the Bonneville seat takes patience and using the outside bolt holes on each seat side. One side won't match up with the welded nuts. You'll have to 'adjust' the manual seat lever by bending it a bit. If it's a power pass. seat, it should be a repeat of the driver seat.
While the seats are out, you should have a slit in the carpet under each seat. Pull the door sill plates, work the carpet around, and run the wiring harness under the carpet. It helps to plug the rat's nest of wiring together outside the car to identify left and right. Basically you have left seat leads, switch panel leads, and right seat leads. The odd black tube with the single gray round connector is for the inflatable lumbar supports. The black canister under the right seat is the inflator motor.
After you've laid the harness and provided new wiring for power and ground, the seats can be installed. I'd wait to bolt the driver seat down until verifying all functions work correctly.
Wiring - do not attempt to connect the Caprice body harness connector into the Pontiac switch box connectors under the front of the left seat. The connector that physically fits together doesn't fit electrically. I didn't use the Caprice connector and the door switch. I'm using the Pontiac switch that will control either seat. You'll see an orange/black stripe wire (hot) and a black wire (ground) terminating in a two position connector at the black box. Apply power and ground appropriately to the switch box. There will another set of orange/black and black wires in the bundle to send power and ground to the pass. seat. All other connectors from the switch box are output to control left and right seat functions.
There is a single gray wire that provides illumination to the switch panel. It's orange illumination, but blue bulb caps should fix that. I'll probably build/scrounge an appropriate console and mount the switchpad there. I'm also considering using a cell phone stalk to mount the switchpad on. There is a smaller guage orange wire that gets power - without connecting it, the power lumbar functions don't work. There is a third black wire that goes to ground.